package org.apache.maven.plugin;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.model.Plugin;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.component.annotations.Component;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.graph.DependencyFilter;
import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.repository.WorkspaceRepository;

/**
 * @author Igor Fedorenko
 * @author Benjamin Bentmann
 */
@Component(role = PluginArtifactsCache.class)
public class DefaultPluginArtifactsCache implements PluginArtifactsCache {

  private static class CacheKey implements Key {

    private final Plugin plugin;

    private final WorkspaceRepository workspace;

    private final LocalRepository localRepo;

    private final List<RemoteRepository> repositories;

    private final DependencyFilter filter;

    private final int hashCode;

    public CacheKey(Plugin plugin, DependencyFilter extensionFilter, List<RemoteRepository> repositories, RepositorySystemSession session) {
      this.plugin = plugin.clone();
      workspace = CacheUtils.getWorkspace(session);
      this.localRepo = session.getLocalRepository();
      this.repositories = new ArrayList<RemoteRepository>(repositories.size());
      for (RemoteRepository repository : repositories) {
        if (repository.isRepositoryManager()) {
          this.repositories.addAll(repository.getMirroredRepositories());
        } else {
          this.repositories.add(repository);
        }
      }
      this.filter = extensionFilter;

      int hash = 17;
      hash = hash * 31 + CacheUtils.pluginHashCode(plugin);
      hash = hash * 31 + hash(workspace);
      hash = hash * 31 + hash(localRepo);
      hash = hash * 31 + CacheUtils.repositoriesHashCode(repositories);
      hash = hash * 31 + hash(extensionFilter);
      this.hashCode = hash;
    }

    @Override
    public String toString() {
      return plugin.getId();
    }

    @Override
    public int hashCode() {
      return hashCode;
    }

    private static int hash(Object obj) {
      return obj != null ? obj.hashCode() : 0;
    }

    @Override
    public boolean equals(Object o) {
      if (o == this) {
        return true;
      }

      if (!(o instanceof CacheKey)) {
        return false;
      }

      CacheKey that = (CacheKey) o;

      return CacheUtils.pluginEquals(plugin, that.plugin) && eq(workspace, that.workspace)
          && eq(localRepo, that.localRepo) && CacheUtils.repositoriesEquals(repositories, that.repositories)
          && eq(filter, that.filter);
    }

    private static <T> boolean eq(T s1, T s2) {
      return s1 != null ? s1.equals(s2) : s2 == null;
    }

  }

  protected final Map<Key, CacheRecord> cache = new HashMap<Key, CacheRecord>();

  public Key createKey(Plugin plugin, DependencyFilter extensionFilter, List<RemoteRepository> repositories,
      RepositorySystemSession session) {
    return new CacheKey(plugin, extensionFilter, repositories, session);
  }

  public CacheRecord get(Key key) throws PluginResolutionException {
    CacheRecord cacheRecord = cache.get(key);

    if (cacheRecord != null && cacheRecord.exception != null) {
      throw cacheRecord.exception;
    }

    return cacheRecord;
  }

  public CacheRecord put(Key key, List<Artifact> pluginArtifacts) {
    if (pluginArtifacts == null) {
      throw new NullPointerException();
    }

    assertUniqueKey(key);

    CacheRecord record = new CacheRecord(Collections.unmodifiableList(new ArrayList<Artifact>(pluginArtifacts)));

    cache.put(key, record);

    return record;
  }

  protected void assertUniqueKey(Key key) {
    if (cache.containsKey(key)) {
      throw new IllegalStateException("Duplicate artifact resolution result for plugin " + key);
    }
  }

  public CacheRecord put(Key key, PluginResolutionException exception) {
    if (exception == null) {
      throw new NullPointerException();
    }

    assertUniqueKey(key);

    CacheRecord record = new CacheRecord(exception);

    cache.put(key, record);

    return record;
  }

  public void flush() {
    cache.clear();
  }

  protected static int pluginHashCode(Plugin plugin) {
    return CacheUtils.pluginHashCode(plugin);
  }

  protected static boolean pluginEquals(Plugin a, Plugin b) {
    return CacheUtils.pluginEquals(a, b);
  }

  public void register(MavenProject project, CacheRecord record) {
    // default cache does not track record usage
  }

}
